Multiple stage interlock type variable resistor

ABSTRACT

A cover, surrounding commonly coupled slider for paired resistors actuated by a common actuator, carries at least one hole permitting access to an adjusting mechanism for shifting one slider relative to the other and to overcome interlock error in a multi-stage interlock type variable resistor.

United States Patent [1 1 Ishikawa et a1, 9

[ NOV. 6, 1973 MULTIPLE STAGE INTERLOCK TYPE VARIABLE RESISTOR Inventors: Sachio lshikawa; Hiroaki Komatsu; Junichi Imura; Hiroshi Takemi, all of Tokyo, Japan Assignee: Alps Electric Co., Ltd., Tokyo, Japan Filed: Aug. 28, 1972 Appl. No.: 283,999

Foreign Application Priority Data Aug. 28, 1971 Japan ..46/6 5 96 9 US. Cl. 338/132, 338/133 Int. Cl 1101c 9/02 Field of Search 338/128, 130, 131,

References Cited UNITED STATES PATENTS 10/1951 Mucher 338/132 X 11/1960 Karg 338/130 X 2/1971 Ichikawa et a1 338/133 Primary Examiner-Bernard A. Gilheany Assistant Examiner-D. A. Tone Att0rneyEliot S. Gerber [57] ABSTRACT A cover, surrounding commonly coupled slider for paired resistors actuated by a common actuator, carries at least one hole permitting access to an adjusting mechanism for shifting one slider relative to the other and to overcome interlock error in a multi-stage interlock type variable resistor.

4 Claims, 12 Drawing Figures 'PATENTEDNUV sum 3.771.093

sum 10F 2 MULTIPLE STAGE INTERLOCK TYPE VARIABLE RESISTOR BACKGROUND OF THE INVENTION I. FIELD OF THE INVENTION The present invention relates to a multiple stage interlock type variable resistor and, more particularly, to a resistor of the rotary or slide type in which the interlock error resulting during assembling of the multiple stage resistor may be readily corrected.

2. DESCRIPTION OF THE PRIOR ART Heretofore, the regulation of the interlocking error,- which is produced when assembling two variable resistors into a common assembly for operation by a single actuator, has been generally corrected prior to assembly of a cover which occurs during the final process in the assembly of the multi-stage variable resistor, so that when an interlocking error is produced between two resistors after assembly, the correction thereof must be carried out by removing the cover at the occasion of each error. This operation is not only extremely troublesome, but also the parts of the variable resistor may be marred or damaged during the removal of the cover which injures the commercial value of the same.

The present invention allows ready correction for the interlocking error after assembly and without the necessity of removing the cover by a simple expedient without appreciably increasing the cost of the resistor.

BRIEF DECRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a multistage variable resistor constituting one embodiment of the present invention.

FIG. 2 is a sectional, side elevation of the resistor of FIG. 1.

FIG. 3 is a perspective view, partially broken away, showing the essential elements of the front and rear slider supports and the roating shaft supporting the same.

FIG. 4 is an enlarged perspective view of portions of the variable resistor of FIG. 1 showing the technique of adjusting the resistor to overcome the interlocking error using a tool T.

FIG. 5 is a perspective view, partially broken away, of the resistor of FIG. 1 slightly modified from the illustration of FIG. 3.

FIG. 6 is an enlarged, perspective view of the essential parts of the resistor of FIG. 1 in modified form for adjusting the resistor which incorporates the elements of FIG. 5 therein.

FIG. 7 is a perspective view of a modified multi-stage variable resistor forming a third embodiment of the present invention.

FIG. 8 is a sectional, side elevational view of the resistor of FIG. 7.

FIG. 9 is a perspective view of a slide type variable resistor forming another embodiment of thepresent invention.

FIG. 10 is an end,sectional elevational view of the variable resistor of FIG. 9.

FIG. 11 is an enlarged perspective view of portions of the resistor of FIGS. 9 and 10.

FIG. 12 is an enlarged perspective view of portions of the resistor of FIG. 9 illustrating the manner of adjustment for interlocking error.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The explanation of the present invention is given with respect to a plurality of embodiments, all of which carry similar elements giving similar numerical designations. In this respect, a rotary type variable resistor is illustrated in FIGS. 1-6 which incorporates the invention in one form. A front stage variable resistor is indicated generally at 1, while a rear stage vaiable resistor is indicated generally at 2, both stages being operated commonly by a rotating shaft 3 which is mounted for rotation within a cover 9 by means of bearing 4. An insulating base plate 1,, for the front stage resistor I supports the bearing 4 and additionally a resistor 5 as well as a conducting plate 6 which are secured thereto in a well known manner.

The slider support 1,, FIG. 3 receives projecting, elongated portion 3a of the rotatable shaft 3, the slider support being formed of insulating material. The slider support carries slider 7 which slidably contacts the resistor 5 during rotation of shaft 3 and the conducting plate 6, the slider 7 being fixed to slider support 1,. A

metal plate 8 is superposed with and enforceably fitted to the front stage slider support 1,,, the metal plate serving as a stop for the rotating shaft as well as an electrical shield between the variable reistors l and 2 of the front and rear stages respectively. A cover 9 which is fixed to the front stage insulating plate 1,, by means of bent tabs 9 is further fixed to the insulating plate 2,, of the rear stage by means of the similar bent over tabs 9 A resistor 5 and a conductive plate 6 are fixed to the insulating base plate 2,, of the rear stage by conventional means in similar fashion to the front stage resistor.

A slider support 2,, of disc form in similar fashion to the slider support 1,, of the front stage, receives the inserted, elongated portion 3,, of rotating shaft 3 in a manner similar to that of the slider support 1,, the slider support 2,, being also formed of an'electrically insulating material. A slider 7 is likewise carried on the slider support 2, and is in contact with resistor 5 in the conducting plate 6 of the rear stage resistor, slider 7 being fixed to slider support 2,.

As seen from the drawing, and in particular in FIG. 3, the rear stage slider support 2,, is coupled to the rotating shaft by receiving the elongated portion 3,, of the rotating shaft 3, which is non-circular in cross-sectional configuration and being provided with two opposed flattened sides, the opening within the rear stage slider support 2,, conforming closely with the elongated portion 3,, of the rotating shaft such that there is no relative rotation between the rear stage slider support 2,, and shaft 3. Further, the rear stage slider support 2,, is carried on'the rotating shaft 3 as is metal plate 1, and the front stage slider support b in such a manner that the three members 2,, l and 8 are pressed against one another. In this regard, the metal plate 8 and one of the front and rear slider supports (in' this case, rear slider support 2 is forceably fitted onto the elongated shaft.

ing shaft 3 relative to plate 8 and the relatively fixed rear slider support 2,. Further, in this regard, a hole 9, (see FIG. 1) is provided within the cover 9 at a position and in longitudinal alignment with slider support 1,, such that the interlocking error may be regulated and eliminated by rotating slider support 1, slightly on the shaft 3 by the act of causing the tip end of tool T to engage the rotatable slider support 1, and by moving tool T in either of two directions as indicated by the double headed arrow in FIG. 4. In order to facilitate the en gagement of the tool T and the slider support 1,, the rotatable slider support 1, is formed with peripheral recesses or teeth. Alternatively, as illustrated in FIG. 6 with a two tip tool, as illustrated in FIG. 5, both peripheries of the slider supports 1, and 2, are provided with recesses or cut portions as at 1, l and 2, with a two prong tool T, FIG. 6, permitting rotation in either direction.

In operation, when the rotating shaft 3 of the variable resistor assembly is rotated, the front and rear stage slider supports 1,, 2, and the metal plate 8 are rotated in unison which also rotates the sliders 7 fixed to the slider supports 1, and 2,. The sliders 7 slide on and in contact with the resistor 5 and conducting plate 6, whereby the resistance values of the front and rear stage variable resistors 1 and 2 are readily varied.

When the resistance values of the front and rear stage variable resistors 1 and 2 do not coincide, due to the error of the parts, or due to error during assembly, thus resulting in an interlocking error subsequent to assembly, the relative position between the slider supports 1, nd 2, may be shifted by inserting the tool T into the hole 9, of the cover 9, causing the tip portion of the tool to engage with at least one of the rotatable slider supports such as rotatable slider support 1,, FIG. 4, and by moving the tool T, a regulation of the interlocking error may be effected externally of the cover without the necessity of disassembling the variable resistor.

Now, a modified embodiment of the rotary type variable resistor as illustrated in FIGS. 7 and 8 will be explained, in which in the drawings and in the description the same reference numerals are employed for the same elements as in the previous embodiment. This embodiment has the same construction as that previously described, except that the front and rear variable resistors 1 and 2 are formed by separate covers 9, and 9 and furthergthe front and rear slider supports 1, and 2, and the sliders 7 are accommodated in separate covers 9, and 9 respectively, so that the detailed explanation is necessarily omitted. In all other ways, the embodiment is similar to that previously described except in this case, it is the slider support 2, that is made rotatable slightly on the rotating shaft 3 and triangular teeth are formed on the periphery of the slider support 2, so that the tool T may be engaged therewith easily, and in this case, th e regulatir1g hole' 9 'is provided in cover 9,.

The present invention is next explained as it is applied to a slide type variable resistor illustrated in FIGS. 9-12 and again, the same reference numerals are employed to illustrate the parts corresponding to those appearing in the rotary type variable resistors previously described. The numeral 1 designates one of the variable resistors, while the other variable resistor is indicated at 2. A box type cover 9 is provided with a rectangular opening 9 and an insulating base plate 10 is fixed to the lower portion of the cover 9. Resistors 5 are fixed in parallel on the insulating base plate 10 as are conducting plates 6 and provided at positions corresponding to each of the resistors 5. A metal plate 8 is fixed to the cover, FIG. 9, which serves as a shield between both variable resistors 1 and 2. A slider 11 is accommodated in the cover 10 and is formed of an insulating material, the slider 11 consisting of a main body 11,, a knob 11, protruding integrally from the main body 11,, and through the openings 9' within the upper surface of cover 9. Sliders 7 are fixed on the lower surfaces of the main body 1 1,, and the movable portion 1 1, of the body and are slidably in contact with the resistors and the conducting plates. Thus, by shifting of knob 11, sliders 7 slide on the resistors 5 and the conducting plate 6, whereby the resistance values of both variable resistors 1 and 2 are changed, FIG. 10. A regulating hole 9, is provided in the cover 9 on the side closest to the movable portion 11, of the slider assembly 11 and the movable portion 11, may be moved relative to the main portion or main body 11,, by engaging the tip portion of a tool T within an engaging hole 11, of a movable portion 11,, which preliminarily passes through a hole 11, of the main body 11,, and moving the tool in one of two directions as shown by the arrows in FIG. 12. Thus, the relative position of the main body l1, and the movable portion 11, of the slider assembly 11, may be shifted. Thus, again it is possible to regulate the resistor to adjust for the interlocking error without removing the cover.

By forming the slider assembly with an elastic synthetic resin, and by wedge fitting the main body 1 1,, and the movable portion 11,, both portions can be coupled firmly without any coupling members required.

Being thus constituted, it is possible, according to the present invention, to carry out simply and easily the regulation and adjustment of interlocking error without the need of disassembling a multi-stage variable resistor, so that the productivity thereof is highly improved.

What is claimed is:

1. In a multi-stage resistor comprising a cover surrounding first and second fixed resistors, first and second sliders mounted within said cover for sliding contact respectively with said first and second resistors, a common actuator for moving said sliders in unison,'and means permitting adjustment in position of one slider relative to the other to correct for interlocking error existing between said resistors, the improvement comprising:

an opening within said cover overlying one of said sliders, and adjustment means carried by said one slider and in alignment with said opening, whereby, insertion of a tool within said opening and in contact with said means,-permits adjustment in the position of one slider with respect to the other. 2. The multi-stage resistor as claimed in claim 1, wherein said first and second fixed resistors are annular in form, a rotatable shaft extends coaxially through said resistors, said sliders are fixed respectively to slider supports carried by said rotating shaft adjacent respective resistors, said means permitting adjustment comprises means fixing one of said slider supports to said rotating shaft and means for mounting the other of said slider supports on said shaft for slight rotation therewith, and means normally biasing said slider supports in frictional contact with each other but permitting, in response to tool insertion, slight relative rotation about sertion of a tool through said cover opening, said movable body opening and said recess within said main body, permits longitudinal shifting of said movable body relative to said main body to correct for said interlocking error.

4. The multi-stage resistor as claimed in claim 3, wherein said main body and said movable body comprise elastic synthetic resin, and wherein said means for coupling said sliders together comprise an interfitting wedge lock between said bodies. 

1. In a multi-stage resistor comprising a cover surrounding first and second fixed resistors, first and second sliders mounted within said cover for sliding contact respectively with said first and second resistors, a common actuator for moving said sliders in unison, and means permitting adjustment in position of one slider relative to the other to correct for interlocking error existing between said resistors, the improvement comprising: an opening within said cover overlying one of said sliders, and adjustment means carried by said one slider and in alignment with said opening, whereby, insertion of a tool within said opening and in contact with said means, permits adjustment in the position of one slider with respect to the other.
 2. The multi-stage resistor as claimed in claim 1, wherein said first and second fixed resistors are annular in form, a rotatable shaft extends coaxially through said resistors, said sliders are fixed respectively to slider supports carried by said rotating shaft adjacent respective resistors, said means permitting adjustment comprises means fixing one of said slider supports to said rotating shaft and means for mounting the other of said slider supports on said shaft for slight rotation therewith, and means normally biasing said slider supports in frictional contact with each other but permitting, in response to tool insertion, slight relative rotation about the shaft axis between said slider supports to correct for interlocking error.
 3. The muti-stage resistor as claimed in claim 1, wherein said resistors comprise spaced parallel elongated members, said first and second sliders comprise an elongated main body and a relatively movable body operatively associated with respective resistors within said cover and defining an assembly, said movable body faces said hole within said cover, said movable body includes an opening in line with said cover hole and in line with a recess within said main body, whereby; insertion of a tool through said cover opening, said movable body opening and said recess within said main body, permits longitudinal shifting of said movable body relative to said main body to correct for said interlocking error.
 4. The multi-stage resistor as claimed in claim 3, wherein said main body and said movable body comprise elastic synthetic resin, and wherein said means for coupling said sliders together coMprise an interfitting wedge lock between said bodies. 